GENETIC IMPROVEMENT OF ORNAMENTAL CROPS WITH ENHANCED HEAT TOLERANCE AND IMPROVED POSTHARVEST QUALITY

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1015784
• Project Start Date: Mar 30, 2018
• Project End Date: Mar 29, 2023
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611

Performing Department
Mid-Florida Research and Education Center

Non Technical Summary
Ornamental plant industry in the U.S. is of importance to agricultural economy with an annual wholesale production value of $4.37 billion. The ornamental horticulture industry is unique in that it produces salable plants from a very wide range of species including floriculture crops, ornamental grasses, lawn or turf grasses and ornamental trees and shrubs as well as edible ornamental fruit trees and vegetables. Florida is one of the leading ornamental plant-producing states in U.S., ornamental horticulture is the largest agricultural sector in Florida. Begonia, Petunia, Lisianthus and snapdragon as well as edible ornamental vegetables are important crops for the ornamental plant industry in Florida and other states. The production and quality of ornamental plants are greatly influenced by environmental conditions; and Florida climate with intense heat and humidity during summer seasons greatly adverse plant growth, which are generally accompanied by severer pest and pathogen problems. The high temperatures in Florida causes great decline in plant growth, non-blooming, and enhanced susceptibility to pathogen in Begonia, Petunia, Lisianthus and snapdragon or causes early bolting for edible foliage vegetable like ornamental lettuce and kale. In addition, Lisianthus and snapdragon are two top ten fresh cutting flowers in the U.S.; however, postharvest senescence limits shelf life and the marketing of fresh cut snapdragon and Lisianthus with ethylene being an important endogenous and exogenous factor that enhances this process. Breeding new varities with better adapatibilty to Florida climatic conditions and with improved post-harvest life quality will be a sustainable solution to better satisfy ormental horticultural production and market demand in Florida. We recently collected ornamental plant germplasm in the southeast US, nationwide, and from international research institute. The main goal of this project is to utlize these germplasm to develop new cultivars with with enhanced heat tolerance and improved post-harvest quality. The release of these new cultivars to growers and stakeholders will improve crop productivity and quality with reduced costs. ?

Animal Health Component

50%

Research Effort Categories

Basic

40%

Applied

50%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
203	2120	1081	100%

Knowledge Area
203 - Plant Biological Efficiency and Abiotic Stresses Affecting Plants;

Subject Of Investigation
2120 - Herbaceous perennials and decorative greens;

Field Of Science
1081 - Breeding;

Keywords

ornamental plants, edible ornamental vegetable, breeding, heat tolerance, post-harvest plant quality

transponson mutagenesis, transposon display, crispr, gene-editing, knock out

begonia, lisianthus, petunia, snapdragon

Goals / Objectives
The main goal of this project is to new cultivars with with enhanced heat tolerance and improved post-harvest quality through convential and advance breeding methods. The specific objectives of this project are: 1) Genetic improvement of Begonia, Lisianthus, Petunia and Snapdragon with enhanced heat stress tolerance; 2) Genetic improvement of Lisianthus and Snapdragon with extended post-harvest plant quality; 3) Genetic improvement of ornamental vegetables with enhanced heat stress tolerance.

Project Methods
Objective 1. Genetic improvement of Begonia, Lisianthus, Petunia and Snapdragon with enhanced heat tolerance. For Begonia and Lisianthus, we will cross-pollinate our heat-tolerant germplasm with different genotypes with better aesthetic values and strong sensitivity to heat stress. Progenies from these crossing will be screened and evaluated for heat tolerance, plant vior, foliage color, blooming date and period etc. Promising breeding lines will be evaluated at different locations. Superior breeding lines will be released as new cultivars. For snapdragon, we will use a temperature dependent-transponson induced lines to generate mutant library. M2 progenies will be used for screening heat tolerance. Superior lines will be released as new cultivars. Transponson-display or genome sequencing will be applied to identify the insertion locus of transposon in these mutants. Maker will be developed for futher marker assist selection breeding. For petunia, genes that regulate heat stress will be gene edited through CRISPR technology in petunia hybrid. Heat tolerance of gene edited mutants will be evaluated; mutants with enhanced heat tolerance but no T-DNA will be released. Objective 2. Genetic improvement of Lisianthus and Snapdragon with extended post-harvest plant quality. For snapdragon, mutant library generated through transposon mutagenesis will be screened for ethylene insensitivity. Mutants will be used for mutation identification and marker development for cross-pollination breeding. Postharvest shelf life and plant performance will be evaluated. Superior lines will be released as new cultivars. For Lisianthus, genes involved in ethylene production and signal transduction will be knockout through CRISPR. Mutants without T-DNA that exhibit ethylene insensitivity will be released as new cultivar or as breeding materials. Objective 3. Genetic improvement of ornamental vegetables with enhanced heat stress tolerance. Genes that regulate early bolting and flowering in ornamental lettuce will be knock out through CRISPR. The mutants will be sequenced for confirmation of gene-edited locus and will be further evaluated for their bolting suppression phenotype under high temperature. The mutants with bolting resistance phenotypes will be evaluated for their foliage color and shape as well as nutrients. Suprior lines will be released as new cultivars.

Progress 03/30/18 to 09/30/18

Outputs
Target Audience:ornamental plant and vegetable growers, peer research scientists, plant breeders, home garderners, extension agents, graduate and undergraudate students, agricultural producting marketing agents, managers and resaerchers of agricultural companies Changes/Problems:No major changes were made for this project. However, depending on the funding availablility,the feasibility of genetic manipulation, and urgent market needs, we have encompass more plant species like petunia, blueberry and hops. We have limited our research activities in lisianthus due to itslimited market in Florida and difficulties in genetic transformation and lack of genetic diversity. Despite these slight changes, our research programs remain focuses on how environmental cues affect plant growth and plant quality. What opportunities for training and professional development has the project provided?This project has trained 6 undergratudents from local Valencia College, 3 UF graduate students, 2 visiting scholars, 2 visiting Ph.D students. How have the results been disseminated to communities of interest?Results from this project were presented at 2018 annual American Society of Horticultural Science conference, 2018 Society of In Vitro Biology Meeting, The 2018 International Conference on Plant and Animal genomes. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? 1) We have have isolated multiple genes todevelopmore than 10 different genetic lines ofpetunia, lettuce, hops and tobbaco to look into their stress tolerance to salinity, drought, heat, whitefly and senescence. We have harvested nine T0/F1 seeds from different genetic lettuce and petunias. These plants were genetically modified through overexpression or silencing functional genes or small RNAs for altered flowering time, coloration and seed germination. In addition, fourteen genetic petunia, tobacco and lettuce with CRISPR gene-editing, overexpression etcare under the stages of T0 greenhouse production or T0 shooting. 2) we have tested different LED light spectrum on hydroponic lettuce production. Different spectrums of light were applied to different types of lettuce. We have found the blue light may inhibit lettuce growth but promote leaf pigment development. Combination of different spectrum lights can generate beneficial effects on hydroponic lettuce growth. 3) we have obtained several heat tolerant begonia. Results from exposure of these begonias to direct sunlight from early June to late october showed the heat tolerant begonia can survive the harsh heat condition in Florida. We have also observed that this one begonia can be hightly resistant to aphid. Breeding progress has made with this heat tolerant begonia to develop new varieties. 4) We have obtained a snapdragon containing active well-studied transposons. The transposition of this type transposon can be activated by low temperature. With this unique characteristics, we develop snapdragon mutant libraries. More than 500 pots of M1 seeds have been grown to develop M2 seeds that will be screened for heat, drought and salt tolerance and ethylene insensitivity.

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Sun H, Duan YK, Qi XC, Zhang LY, Huo HQ and Gong HJ (2018), Isolation and functional characterization of CsLsi2, a silicon efflux transporter gene. Annals of Botany, 122: 641-648.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Li P, Yang H, Liu GJ, Ma WZ, Li CH, Huo HQ, He JF, Liu L (2018) PpSARK Regulates Moss Senescence and Salt Tolerance through ABA Related Pathway. Int. J. Mol. Sci. 19(9): 2609
• Type: Journal Articles Status: Published Year Published: 2018 Citation: ⿢ Zuo CW, Deng GM, Li B, Huo HQ, Li CY, Hu CH, Kuang RB, Yang QS, Dong T, Sheng O, Yi GJ (2018) Germplasm screening of Musa spp. for resistance to Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4). Eur J Plant Pathol 151:723⿿734
• Type: Journal Articles Status: Published Year Published: 2018 Citation: ⿢ Bertier LD, Ron M, Huo HQ, Bradford KJ, Michelmore RW (2018) High resolution analysis of the efficiency, heritability and editing outcomes of CRISPR/CAS9-induced modifications of NCED4 in lettuce (Lactuca sativa) G3: Genes, Genomics, Genetics 8(5):1513-1521
• Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Huo HQ, (2018), Genetic Improvement of Lettuce through QTL Mapping and Biotechnological Tools, UF-HZAU 1st Bilateral Symposium, Dec. 7-11, 2018, Wuhan, China
• Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Huo HQ, Niroula M, Hill T, Li J, Nguyen, LD, Truco M, Michelmore RW, Bradford KJ, (2018), Genetic Regulation of Lettuce Seed Germination by LsGA2ox2 under Darkness, 2018 In Vitro Biology Meeting, June 2-6, 2018, Saint Louis, USA.
• Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Huo HQ, Niroula M, Hill T, Li J, Nguyen, LD, Truco M, Michelmore RW, Bradford KJ (2018), LsGA2ox2 Regulates Lettuce Seed Germination Under Darkness. 2018 ASHS annual meeting, July 31-Aug.3, 2018, Washington D.C. USA
• Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Bradford KJ, Huo HQ, Niroula M, Hill T, Li J, Nguyen, LD, Truco M, Michelmore RW (2018), Dark Inhibition of Lettuce Seed Germination Is Controlled by LsGA2ox2, 6th Plant Dormancy Symposium, October 23-26, 2018, Kyoto, Japan.
• Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Li JC, Nguyen LD, Mou BQ, Huo HQ (2018), Development of Variegated Lettuce Using CRISPR/Cas9 Technology, 2018 ASHS annual meeting, July 31-Aug.3, 2018, Washington D.C. USA. (Abstract)